The Federal Aviation Administration (FAA) officially lifted its nationwide ground stop Friday, November 13, allowing departing flights to resume after a communications outage disrupted air traffic control operations across the United States.

The ground stop was initially imposed after a telecommunications failure affected all 22 regional Air Route Traffic Control Centers, which manage aircraft traveling between airports nationwide. The disruption forced the FAA to suspend departures at airports across the country while technicians worked to restore the affected communications systems.

Transportation Secretary Sean Duffy confirmed that the communications issue had affected all 22 regional facilities. Homeland Security Secretary Markwayne Mullin described the incident as a telecommunications outage and said officials had found no indication, as of yet, that it was a deliberate or "nefarious" attack.

The outage caused widespread disruption to air travel, with more than 4,000 flights canceled. Airlines, passengers, and professional and college sports teams faced significant travel uncertainty as officials worked to restore normal operations.

Earlier Friday evening, the FAA began allowing flights to depart through coordination with the Air Traffic Control System Command Center as en route facilities recovered. The agency subsequently lifted the nationwide ground stop, ending the broad departure restrictions imposed during the communications failure.

Officials have not publicly confirmed the precise cause of the outage. Reports indicated that a network update may have caused the private communications system operated by defense contractor L3Harris to reboot and crash, but that explanation has not been officially confirmed.